C Entry-level student management system

Trainer, a student management system that is no longer simple. Hope the experts do not spray.

# Include <stdio. h> # include <stdlib. h> # include <string. h> # define num 20 // total number of users # define Add 1 // added tag # define del 2 // deleted tag # define UPD 3 // updated tag # define ser 4 // tag for a single search # define all 5 // tag for all search # define exit 6 // tag for exit # define Yes 1 // operation successful # define no 0 // operation failed // Student Score structure struct info {float Chinese; float math; float English ;}; // basic student information struct, nested Student Score struct Stu {int ID; char * Name; char sex; struct info * In ;}; typedef struct Stu stu_s; Typedef struct info info_ I; // use the global variable stu_s * lib [num] for the student information library; int Len = sizeof (LIB)/sizeof (LIB [0]); int add (stu_s * t) // Add a student function. I use (ID-1) to indicate the position in the student information library, saves traversal trouble {If (LIB [(t-> ID)-1] = NULL) // if the information library is empty, add it directly, return Yes {lib [T-> ID-1] = (stu_s *) malloc (sizeof (struct Stu) * 1 ); lib [T-> ID-1]-> name = (char *) malloc (sizeof (char) * 10 ); lib [T-> ID-1]-> In = (info_ I *) malloc (sizeof (struct info) * 1); LIB [T-> ID-1]-> I D = T-> ID; LIB [T-> ID-1]-> name = T-> name; lib [T-> ID-1]-> sex = T-> sex; lib [T-> ID-1]-> In-> Chinese = T-> In-> Chinese; lib [T-> ID-1]-> In-> math = T-> In-> math; lib [T-> ID-1]-> In-> English = T-> In-> English; return yes;} // if the information library is not empty, the student already exists. Return noprintf ("** failed to add ** \ n"); printf ("^ sorry! This student already exists! ^ \ N "); return no;} int Delete (int id) // deletes a student by passing in the ID {If (LIB [ID-1]! = NULL) // if the student information is not empty, delete it directly, and return YES {free (LIB [ID-1]); LIB [ID-1] = NULL; // memmove (LIB + J, lib + J + 1, len-j); Return yes;} // otherwise, the student does not exist, return noprintf ("** failed to delete ** \ n"); printf ("^ sorry, this student does not exist! ^ \ N "); return no;} int beforeupd (int id) // before updating student information, check whether the student exists before proceeding to the next step, yes {If (LIB [ID-1] = NULL) {printf ("** update failed ** \ n") is returned "); printf ("^ sorry! This student does not exist! ^ \ N "); return no;} return yes;} int Update (int id, stu_s * t) // The student already exists, directly update the student information and return YES {lib [ID-1]-> id = T-> ID; LIB [ID-1]-> name = T-> name; lib [ID-1]-> sex = T-> sex; LIB [ID-1]-> In-> Chinese = T-> In-> Chinese; lib [ID-1]-> In-> math = T-> In-> math; lib [ID-1]-> In-> English = T-> In-> English; return yes;} int search (int id) // search for {If (LIB [ID-1]! = NULL) // if the student information is not empty, print it directly, and return YES {printf ("ID = % d student information: \ n", ID ); printf ("student ID: % d, name: % s, Gender: % C, language: %. 2f, mathematics: %. 2f, English: %. 2f \ n ", lib [ID-1]-> ID, lib [ID-1]-> name, lib [ID-1]-> sex, lib [ID-1]-> In-> Chinese, lib [ID-1]-> In-> math, lib [ID-1]-> In-> English ); return yes;} // otherwise, the student does not exist. noprintf ("** query failed ** \ n") is returned; printf ("^ sorry! This student does not exist! ^ \ N "); return no;} void printall () // query all student information {Int J; For (j = 0; j <Len; ++ J) // traverse the {If (LIB [J]! = NULL) // print all the information not empty. {printf ("student ID: % d, name: % s, Gender: % C, language: %. 2f, mathematics: %. 2f, English: %. 2f \ n ", lib [J]-> ID, lib [J]-> name, lib [J]-> sex, lib [J]-> In-> Chinese, lib [J]-> In-> math, lib [J]-> In-> English) ;}} int menu () // menu function, {printf ("@ select a menu label: \ n"); printf ("1: Add student information. \ N "); printf (" 2: delete student information. \ N "); printf (" 3: Update student information. \ N "); printf (" 4: Query individual student information. \ N "); printf (" 5: Query all student information. \ N "); printf (" 6: exit the system. \ N "); printf ("========================================== =============================\ N "); int num; scanf ("% d", & num); getchar (); Return num;} int main (void) {// declare a student information constructor, and allocate the dynamic memory stu_s * s; S = (stu_s *) malloc (sizeof (struct Stu) * 1); s-> name = (char *) malloc (sizeof (char) * 10); s-> In = (info_ I *) malloc (sizeof (struct info) * 1 ); printf ("=============================== * student management system * ================== ===========\ N "); int num; // set a menu label to operate label: num cyclically = Menu (); Switch (Num) // capture the menu label entered by the user {Case Add: // Add the label printf ("Enter the student ID :"); scanf ("% d", & S-> ID); getchar (); printf ("Enter name:"); s-> name = (char *) malloc (sizeof (char) * 10); scanf ("% s", S-> name); getchar (); printf ("Enter Gender :"); scanf ("% C", & S-> sex); getchar (); printf ("enter Chinese score:"); scanf ("% F ", & S-> In-> Chinese); getchar (); printf ("Enter the mathematical score:"); scanf ("% F ", & S-> In-> math); getchar (); printf ("Enter the English score:"); scanf ("% F ", & S-> In-> English); getchar (); If (S-> ID> 0 & S-> id <= num) {int isadd = add (s); If (isadd = Yes) printf ("***** congratulations, student information has been added! * ***** \ N ");} else {printf (" ****** sorry, the ID you entered is out of the range! * ***** \ N ");} printf ("========================================== =============================\ N "); goto label; Case DEL: // Delete the label printf ("Enter the student ID to delete:"); int IDD; scanf ("% d", & IDD ); getchar (); If (IDD> 0 & IDD <= num) {int isdel = Delete (IDD); If (isdel = Yes) {printf ("***** congratulations, student information has been deleted! * ***** \ N ") ;}} else {printf (" ****** sorry, the ID you entered is out of the range! * ***** \ N ");} printf ("========================================== =============================\ N "); goto label; Case UPD: // update the label printf ("Enter the student ID to be updated:"); int IDU; scanf ("% d", & IDU ); getchar (); If (IDU> 0 & IDU <= num) {int isok = beforeupd (IDU); If (isok = Yes) {S-> id = IDU; printf ("Enter name:"); s-> name = (char *) malloc (sizeof (char) * 10); scanf ("% s ", s-> name); getchar (); printf ("Enter Gender:"); scanf ("% C", & S-> sex); getchar (); printf ("Enter the Chinese score :"); Scanf ("% F", & S-> In-> Chinese); getchar (); printf ("Enter the mathematical score:"); scanf ("% F ", & S-> In-> math); getchar (); printf ("Enter the English score:"); scanf ("% F ", & S-> In-> English); getchar (); int isupd = Update (IDU, S); If (isupd = Yes) printf ("***** congratulations, student information has been updated! * ***** \ N ") ;}} else {printf (" ****** sorry, the ID you entered is out of the range! * ***** \ N ");} printf ("========================================== =============================\ N "); goto label; Case SER: printf ("Enter the student ID to query:"); int IDs; scanf ("% d", & IDs ); if (IDs> 0 & IDs <num) {int isser = search (IDS);} else {printf ("***** sorry, the ID you entered is out of the range! * ***** \ N ");} printf ("========================================== =============================\ N "); goto label; case all: printf ("all student information: \ n"); printall (); printf ("========================================== =============================\ N "); goto label; goto label; Case Exit: break;} return 0 ;}